linux/net/phonet/pn_netlink.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * File: pn_netlink.c
   4 *
   5 * Phonet netlink interface
   6 *
   7 * Copyright (C) 2008 Nokia Corporation.
   8 *
   9 * Authors: Sakari Ailus <sakari.ailus@nokia.com>
  10 *          Remi Denis-Courmont
  11 */
  12
  13#include <linux/kernel.h>
  14#include <linux/netlink.h>
  15#include <linux/phonet.h>
  16#include <linux/slab.h>
  17#include <net/sock.h>
  18#include <net/phonet/pn_dev.h>
  19
  20/* Device address handling */
  21
  22static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
  23                     u32 portid, u32 seq, int event);
  24
  25void phonet_address_notify(int event, struct net_device *dev, u8 addr)
  26{
  27        struct sk_buff *skb;
  28        int err = -ENOBUFS;
  29
  30        skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
  31                        nla_total_size(1), GFP_KERNEL);
  32        if (skb == NULL)
  33                goto errout;
  34        err = fill_addr(skb, dev, addr, 0, 0, event);
  35        if (err < 0) {
  36                WARN_ON(err == -EMSGSIZE);
  37                kfree_skb(skb);
  38                goto errout;
  39        }
  40        rtnl_notify(skb, dev_net(dev), 0,
  41                    RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);
  42        return;
  43errout:
  44        rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_IFADDR, err);
  45}
  46
  47static const struct nla_policy ifa_phonet_policy[IFA_MAX+1] = {
  48        [IFA_LOCAL] = { .type = NLA_U8 },
  49};
  50
  51static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
  52                     struct netlink_ext_ack *extack)
  53{
  54        struct net *net = sock_net(skb->sk);
  55        struct nlattr *tb[IFA_MAX+1];
  56        struct net_device *dev;
  57        struct ifaddrmsg *ifm;
  58        int err;
  59        u8 pnaddr;
  60
  61        if (!netlink_capable(skb, CAP_NET_ADMIN))
  62                return -EPERM;
  63
  64        if (!netlink_capable(skb, CAP_SYS_ADMIN))
  65                return -EPERM;
  66
  67        ASSERT_RTNL();
  68
  69        err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
  70                                     ifa_phonet_policy, extack);
  71        if (err < 0)
  72                return err;
  73
  74        ifm = nlmsg_data(nlh);
  75        if (tb[IFA_LOCAL] == NULL)
  76                return -EINVAL;
  77        pnaddr = nla_get_u8(tb[IFA_LOCAL]);
  78        if (pnaddr & 3)
  79                /* Phonet addresses only have 6 high-order bits */
  80                return -EINVAL;
  81
  82        dev = __dev_get_by_index(net, ifm->ifa_index);
  83        if (dev == NULL)
  84                return -ENODEV;
  85
  86        if (nlh->nlmsg_type == RTM_NEWADDR)
  87                err = phonet_address_add(dev, pnaddr);
  88        else
  89                err = phonet_address_del(dev, pnaddr);
  90        if (!err)
  91                phonet_address_notify(nlh->nlmsg_type, dev, pnaddr);
  92        return err;
  93}
  94
  95static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
  96                        u32 portid, u32 seq, int event)
  97{
  98        struct ifaddrmsg *ifm;
  99        struct nlmsghdr *nlh;
 100
 101        nlh = nlmsg_put(skb, portid, seq, event, sizeof(*ifm), 0);
 102        if (nlh == NULL)
 103                return -EMSGSIZE;
 104
 105        ifm = nlmsg_data(nlh);
 106        ifm->ifa_family = AF_PHONET;
 107        ifm->ifa_prefixlen = 0;
 108        ifm->ifa_flags = IFA_F_PERMANENT;
 109        ifm->ifa_scope = RT_SCOPE_LINK;
 110        ifm->ifa_index = dev->ifindex;
 111        if (nla_put_u8(skb, IFA_LOCAL, addr))
 112                goto nla_put_failure;
 113        nlmsg_end(skb, nlh);
 114        return 0;
 115
 116nla_put_failure:
 117        nlmsg_cancel(skb, nlh);
 118        return -EMSGSIZE;
 119}
 120
 121static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 122{
 123        struct phonet_device_list *pndevs;
 124        struct phonet_device *pnd;
 125        int dev_idx = 0, dev_start_idx = cb->args[0];
 126        int addr_idx = 0, addr_start_idx = cb->args[1];
 127
 128        pndevs = phonet_device_list(sock_net(skb->sk));
 129        rcu_read_lock();
 130        list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 131                u8 addr;
 132
 133                if (dev_idx > dev_start_idx)
 134                        addr_start_idx = 0;
 135                if (dev_idx++ < dev_start_idx)
 136                        continue;
 137
 138                addr_idx = 0;
 139                for_each_set_bit(addr, pnd->addrs, 64) {
 140                        if (addr_idx++ < addr_start_idx)
 141                                continue;
 142
 143                        if (fill_addr(skb, pnd->netdev, addr << 2,
 144                                         NETLINK_CB(cb->skb).portid,
 145                                        cb->nlh->nlmsg_seq, RTM_NEWADDR) < 0)
 146                                goto out;
 147                }
 148        }
 149
 150out:
 151        rcu_read_unlock();
 152        cb->args[0] = dev_idx;
 153        cb->args[1] = addr_idx;
 154
 155        return skb->len;
 156}
 157
 158/* Routes handling */
 159
 160static int fill_route(struct sk_buff *skb, struct net_device *dev, u8 dst,
 161                        u32 portid, u32 seq, int event)
 162{
 163        struct rtmsg *rtm;
 164        struct nlmsghdr *nlh;
 165
 166        nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), 0);
 167        if (nlh == NULL)
 168                return -EMSGSIZE;
 169
 170        rtm = nlmsg_data(nlh);
 171        rtm->rtm_family = AF_PHONET;
 172        rtm->rtm_dst_len = 6;
 173        rtm->rtm_src_len = 0;
 174        rtm->rtm_tos = 0;
 175        rtm->rtm_table = RT_TABLE_MAIN;
 176        rtm->rtm_protocol = RTPROT_STATIC;
 177        rtm->rtm_scope = RT_SCOPE_UNIVERSE;
 178        rtm->rtm_type = RTN_UNICAST;
 179        rtm->rtm_flags = 0;
 180        if (nla_put_u8(skb, RTA_DST, dst) ||
 181            nla_put_u32(skb, RTA_OIF, dev->ifindex))
 182                goto nla_put_failure;
 183        nlmsg_end(skb, nlh);
 184        return 0;
 185
 186nla_put_failure:
 187        nlmsg_cancel(skb, nlh);
 188        return -EMSGSIZE;
 189}
 190
 191void rtm_phonet_notify(int event, struct net_device *dev, u8 dst)
 192{
 193        struct sk_buff *skb;
 194        int err = -ENOBUFS;
 195
 196        skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
 197                        nla_total_size(1) + nla_total_size(4), GFP_KERNEL);
 198        if (skb == NULL)
 199                goto errout;
 200        err = fill_route(skb, dev, dst, 0, 0, event);
 201        if (err < 0) {
 202                WARN_ON(err == -EMSGSIZE);
 203                kfree_skb(skb);
 204                goto errout;
 205        }
 206        rtnl_notify(skb, dev_net(dev), 0,
 207                          RTNLGRP_PHONET_ROUTE, NULL, GFP_KERNEL);
 208        return;
 209errout:
 210        rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_ROUTE, err);
 211}
 212
 213static const struct nla_policy rtm_phonet_policy[RTA_MAX+1] = {
 214        [RTA_DST] = { .type = NLA_U8 },
 215        [RTA_OIF] = { .type = NLA_U32 },
 216};
 217
 218static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
 219                      struct netlink_ext_ack *extack)
 220{
 221        struct net *net = sock_net(skb->sk);
 222        struct nlattr *tb[RTA_MAX+1];
 223        struct net_device *dev;
 224        struct rtmsg *rtm;
 225        int err;
 226        u8 dst;
 227
 228        if (!netlink_capable(skb, CAP_NET_ADMIN))
 229                return -EPERM;
 230
 231        if (!netlink_capable(skb, CAP_SYS_ADMIN))
 232                return -EPERM;
 233
 234        ASSERT_RTNL();
 235
 236        err = nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
 237                                     rtm_phonet_policy, extack);
 238        if (err < 0)
 239                return err;
 240
 241        rtm = nlmsg_data(nlh);
 242        if (rtm->rtm_table != RT_TABLE_MAIN || rtm->rtm_type != RTN_UNICAST)
 243                return -EINVAL;
 244        if (tb[RTA_DST] == NULL || tb[RTA_OIF] == NULL)
 245                return -EINVAL;
 246        dst = nla_get_u8(tb[RTA_DST]);
 247        if (dst & 3) /* Phonet addresses only have 6 high-order bits */
 248                return -EINVAL;
 249
 250        dev = __dev_get_by_index(net, nla_get_u32(tb[RTA_OIF]));
 251        if (dev == NULL)
 252                return -ENODEV;
 253
 254        if (nlh->nlmsg_type == RTM_NEWROUTE)
 255                err = phonet_route_add(dev, dst);
 256        else
 257                err = phonet_route_del(dev, dst);
 258        if (!err)
 259                rtm_phonet_notify(nlh->nlmsg_type, dev, dst);
 260        return err;
 261}
 262
 263static int route_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 264{
 265        struct net *net = sock_net(skb->sk);
 266        u8 addr;
 267
 268        rcu_read_lock();
 269        for (addr = cb->args[0]; addr < 64; addr++) {
 270                struct net_device *dev = phonet_route_get_rcu(net, addr << 2);
 271
 272                if (!dev)
 273                        continue;
 274
 275                if (fill_route(skb, dev, addr << 2, NETLINK_CB(cb->skb).portid,
 276                               cb->nlh->nlmsg_seq, RTM_NEWROUTE) < 0)
 277                        goto out;
 278        }
 279
 280out:
 281        rcu_read_unlock();
 282        cb->args[0] = addr;
 283
 284        return skb->len;
 285}
 286
 287int __init phonet_netlink_register(void)
 288{
 289        int err = rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_NEWADDR,
 290                                       addr_doit, NULL, 0);
 291        if (err)
 292                return err;
 293
 294        /* Further rtnl_register_module() cannot fail */
 295        rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_DELADDR,
 296                             addr_doit, NULL, 0);
 297        rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_GETADDR,
 298                             NULL, getaddr_dumpit, 0);
 299        rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_NEWROUTE,
 300                             route_doit, NULL, 0);
 301        rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_DELROUTE,
 302                             route_doit, NULL, 0);
 303        rtnl_register_module(THIS_MODULE, PF_PHONET, RTM_GETROUTE,
 304                             NULL, route_dumpit, 0);
 305        return 0;
 306}
 307